A stick slip condition or phenomenon is the spontaneous jerking motion that occurs while two objects are sliding over each other. Stick slip is caused by the surfaces alternating between sticking to each other and sliding over each other, with a corresponding change in the friction coefficient between them. The static friction coefficient between two surfaces can be larger than the kinetic friction coefficient. If an applied force is large enough to overcome the static friction, then the reduction of the friction to the kinetic friction can cause a sudden jump in the velocity.
Stick slip can occur during drilling operations and adversely affects the overall drilling performance by causing the premature failure of drilling components. Drillers desire to predict and/or reduce stick slip conditions to enhance drilling activities. The physics behind the actual phenomenon can be complicated due to differing borehole geometries, differing geological conditions and equipment used.